A problem with such a connection device is that all surfaces that are wet by milk, must in order to fulfil set up hygienic requirements be able to be cleansed during washing of the pipeline milking plant, which is performed such that washing solution is rinsed through the whole plant.
One known connection device is described in SE-C-174 540 and comprises a valve housing mounted on a milk line and a connection member connected to a milking unit. During connection of the connection member to the valve housing a knob of a connection member must be accurately fitted into a recess of a substantially semi-spherical body, which must thereafter be turned by hand power to a position where an opening of the connection member is right before an opening of the valve housing, such that communication between the milk line and the milking unit is created.
The described connection device has a disadvantage therein that the connection member must be turned together with the said semi-spherical body, being an undesired complication of the connection operation.
In DE-A-2 637 117 is certainly described a connection device free of turning movement, but also this one suffers from a serious drawback, since two nipples of the connection member must be accurately fitted into two corresponding holes in the valve housing before connection can be performed. The milker must furthermore perform two movements in order to connect the connection member to the valve housing; first a movement towards the valve housing, thereafter a vertical movement.
Another known connection device is described in SE-C-170 120 and comprises a valve housing on a line and a connection member. When the connection member is to be connected to the valve housing, the connection member must first be fitted into a circular-cylindrical drilling in the valve housing. After that guiding means of the connection member have to be carefully fitted into corresponding guiding means of the valve housing.
In DE-A-4 003 367 there is a further connection device free of turning movement described. This one is equipped with a catching member, which however, as shown in the figures, is intended to be mounted vertically on a milk line, which member unnecessary lifts for the milker. Furthermore, the described connection member cannot be connected to the valve housing in one movement, since it first has to be brought in one direction up to the valve housing and thereafter in a completely different direction in the valve housing.
The firm R. J. Fullwood & Bland Ltd. manufactures and markets a connection device comprising a valve housing named "Dari-line Station" and a connection member having the designation "Dari-line Glide". The connection member can certainly be connected to the valve housing in one single movement, but the valve housing is shaped such that during connection of the connection member, as well as during removal of the same, a large amount of surrounding air is allowed to be sucked into the milk line, which is not desired.
When a milking unit is moved from one cow to another, a small amount of milk nearly always stays in the milk tube that connects the milking unit to the connection member. During connection of the connection member to the milk line, which is connected to a vacuum source, the small amount of milk is slung towards the valve housing. The valve housing marketed by Fullwood is designed such that the small amount of milk hits surfaces of the valve housing that cannot be cleansed automatically during washing of the milking plant but have to be cleansed manually after each milking for avoiding growth of bacteria thereon.
One object of the invention is to achieve a connection device of the kind in question, by means of which the connection device can be easily connected to the valve housing, preferably by movement of the connection member in substantially one single direction.
Another object of the invention is to achieve a cooperation between the connection member and a valve present in the valve housing, such that inlet of air into the milk line and milk leakage during connection and disconnection of the connection member can be avoided or at least be minimized.
A further object of the invention is to avoid t milk contaminates the connection device, such that only automatic washing of the pipeline milking equipment is necessary.
In accordance with the invention a connection device for connection of a milking unit to a milk line in a pipeline milking plant is suggested, the milk line having a wall that surrounds a channel and has a hole, and the milking unit having a cavity for extracted milk, comprising
a valve housing having an opening and being adapted to be fastened to the milk line in such a way that the opening communicates with the channel of the milk line via the hole in the wall of the milk line; PA1 a connection member having a through passage and being adapted to be connected to the milking unit in such a way that the passage communicates with said cavity of the milking unit, the connection member further being adapted to be releasably connected to the valve housing in such a way that the passage communicates with the opening of the valve housing; PA1 guiding means adapted during a translational movement of the connection member to positively guide the connection member in relation to the valve housing in a predetermined movement path from a first position to a second position, in which latter position the passage of the connection member communicates with the channel of the milk line via the opening of the valve housing and the hole in the wall of the milk line; and PA1 a sliding valve which is adapted to cover said opening of the valve housing in a closing position, such that it communicates with the passage of the connection member, and PA1 a coupling device adapted, during a positively controlled translational movement of the connection member, when this is in an intermediate position between said first and second positions to connect the connection member to the sliding valve in such a way that the sliding valve is positively connected to the connection member, the coupling device further being adapted to release the connection member from the sliding valve in said intermediate position of the connection member, when this is moved in a direction from said second towards said first position.
Suitably the coupling device comprises at least one coupling member, which in said intermediate position of the connection member is freely movable between a connecting position and a disconnecting position when not actuated, but is adapted, in said connecting position, to be kept substantially immovable relative to the sliding valve and the connection member, when the connection member actuates the sliding valve during the movement of the sliding valve between its intermediate position and its said second position. Hereby is achieved a secure connection of the connection member to the sliding valve.
Preferably, the valve housing is shaped such that it keeps the clutch member in said connecting position when the connection member is between its intermediate position and said second position. Hereby the sliding valve is prevented from undesiredly coming loose from the connection member during its movement.
Advantageously, a catch member is provided to guide the connection member to said first position during movement of the connection member towards the valve housing, such that the connection member gets into engagement with the valve housing by means of said guiding means. Hereby is achieved a connection member, by means of which the connection member can be connected to the valve housing in one single movement.